A pipe string, apparatus and method for establishing a chemical packer in an annulus outside a screen pipe

Abstract

The application provides a pipe string, device and method for establishing a chemical packer in an annulus outside a screen pipe, the pipe string comprising at least one rubber plug unit arranged at the front end of the pipe string and at least one water control completion unit arranged at the rear end of the pipe string; the rubber plug unit comprises a cylinder, a first control rubber plug, a second control rubber plug and a plugging agent, the first control rubber plug and the second control rubber plug are respectively connected to the two ends of the cylinder, and the plugging agent is arranged between the first control rubber plug and the second control rubber plug; the water control completion unit comprises a constant pressure switch valve and two packers, in a use state, the two packers are set in the screen pipe, under the action of first hydraulic pressure, the first control rubber plug and the second control rubber plug can move downward to the position of the constant pressure switch valve, under the action of second hydraulic pressure, the first control rubber plug moves downward to extrude the plugging agent, and the plugging agent flows out through the constant pressure switch valve. The chemical packer can be established in the annulus outside the screen pipe, and axial channeling control of the annulus outside the screen pipe can be realized.

Description

Technical Field

[0001] This invention relates to a tubular column, apparatus, and method for establishing a chemical packer in the outer annulus of a sieve tube. Background Technology

[0002] In the field of oil and gas well completion technology, slotted screen completion is a commonly used method for horizontal well completion. Slotted screen completion involves running slotted screens into the production horizontal section of the oil well. Slotted screens not only offer advantages such as a large exposed seepage area in the producing formation, low gas inflow resistance, minimal production loss, and protection of the oil and gas layer from damage caused by cementing operations, but also effectively control sand production and prevent wellbore collapse. Due to its simplicity, ease of operation, and low cost, this method is currently widely used for horizontal well completion. Summary of the Invention

[0003] The inventors of this invention have discovered that, under slotted screen completion conditions, as oil and gas development progresses, edge and bottom water can surge along high-permeability layers or reservoir fractures into the wellbore, resulting in high water cuts or water flooding in the oil and gas well. Due to the heterogeneity of the oil reservoir and differences in extraction methods, edge and bottom water propagates unevenly along high-permeability layers and zones. Furthermore, because the annulus outside the slotted screen is connected to the inside of the slotted screen, edge and bottom water can axially flow through the annulus, hindering later-stage downhole operations such as water shut-off and reservoir segmentation in horizontal wells. In view of the above problems, it is necessary to propose a string, device, and method for establishing a chemical packer in the annulus outside the slotted screen to solve or partially solve these problems. The technical solution proposed by this invention is as follows:

[0004] As a first aspect of the present invention, the present invention provides a string for establishing a chemical packer in the outer annulus of a screen tube, including at least one rubber plug unit disposed at the front end of the string and at least one water control completion unit disposed at the rear end of the string.

[0005] The rubber stopper unit includes a cylinder, a first control rubber stopper, a second control rubber stopper, and a plugging agent. The first control rubber stopper and the second control rubber stopper are respectively connected to both ends of the cylinder, and the plugging agent is disposed between the first control rubber stopper and the second control rubber stopper.

[0006] The water control completion unit includes a constant pressure switching valve and two packers, with the constant pressure switching valve connected between the two packers;

[0007] In use, the two packers are seated on the screen tube. Under the action of the first hydraulic pressure, the first control plug and the second control plug can descend to the position of the constant pressure switch valve. Under the action of the second hydraulic pressure, the first control plug descends and squeezes the plugging agent, causing the plugging agent to flow out through the constant pressure switch valve. The second hydraulic pressure is greater than the first hydraulic pressure.

[0008] In one or more embodiments, the rubber stopper unit further includes a separating fluid disposed between the plugging agent and the first control rubber stopper and between the plugging agent and the second control rubber stopper.

[0009] In one or more embodiments, both the first control rubber plug and the second control rubber plug include a connector, a short section, a rubber plug assembly, and a plug.

[0010] The short section is connected to the connector;

[0011] The rubber plug assembly is disposed inside the short section and is connected to the short section by a rubber plug shear pin;

[0012] The plug is located at the tail end of the rubber stopper assembly and is connected to the rubber stopper assembly via a plug shear pin.

[0013] In one or more embodiments, the rubber stopper assembly includes a rubber stopper cap, a rubber stopper, a rubber stopper base, a core tube, and a rubber stopper sleeve;

[0014] The rubber stopper cap and the rubber stopper base are respectively connected to both ends of the core tube, and the rubber stopper cap is connected to the short section through the rubber stopper shear pin;

[0015] The rubber stopper is disposed outside the core tube and is connected to the rubber stopper cap and the rubber stopper base respectively, and the rubber stopper abuts against the inner wall of the short section;

[0016] The rubber stopper sleeve is connected to the rubber stopper cap and the rubber stopper respectively;

[0017] The plug is disposed inside the rubber stopper base and is connected to the rubber stopper base by the plug shear pin.

[0018] In one or more embodiments, a first seal is provided between the short section and the connector, a second seal is provided between the rubber stopper cap and the short section, a third seal is provided between the core tube and the rubber stopper cap and between the core tube and the rubber stopper base, and a fourth seal is provided between the plug and the rubber stopper base.

[0019] In one or more embodiments, the constant pressure switching valve includes an upper connector, a lower connector, a connecting sleeve, and a piston assembly;

[0020] The upper connector and the lower connector are respectively connected to both ends of the connecting sleeve;

[0021] The connecting sleeve is provided with a liquid outlet hole, and the piston assembly is provided correspondingly to the liquid outlet hole and is connected to the connecting sleeve by an outer pin.

[0022] In one or more embodiments, the piston assembly includes an outer piston, a spring, and a connecting ring;

[0023] The outer piston is connected to the connecting sleeve via the outer pin, and the size of the lower connector matches the size of the second control rubber plug.

[0024] The connecting ring is connected to the lower connector;

[0025] One end of the spring is fixedly connected to the connecting ring, and the other end abuts against the outer piston.

[0026] In one or more embodiments, the constant pressure switching valve further includes an inner piston;

[0027] The inner piston is disposed inside the connecting sleeve and is connected to the connecting sleeve by an inner pin;

[0028] The size of the inner piston matches the size of the rubber stopper of the first control stopper.

[0029] In one or more embodiments, a fifth sealing element is provided between the upper connector and the connecting sleeve, between the inner piston and the connecting sleeve, between the lower connector and the connecting sleeve, and between the connecting sleeve and the outer piston.

[0030] In one or more embodiments, the string for establishing a chemical packer in the outer annulus of the screen tube further includes a constant pressure bottom valve, which is located at the tail end of the water control completion unit and connected to the water control completion unit.

[0031] In one or more embodiments, the tubing for establishing a chemical packer in the outer annulus of the sieve tube further includes a guide shoe connected to the constant pressure bottom valve.

[0032] In one or more embodiments, the at least one rubber plug unit includes a first rubber plug unit and a second rubber plug unit, and the at least one water-controlled well completion unit includes a first water-controlled well completion unit and a second water-controlled well completion unit;

[0033] The distance between the first rubber plug unit and the second rubber plug unit is the same as the distance between the first water-controlled completion unit and the second water-controlled completion unit;

[0034] The first rubber stopper unit includes a first plugging agent, and the second rubber stopper unit includes a second plugging agent.

[0035] In one or more embodiments, the string for establishing a chemical packer in the outer annulus of the screen tube further includes a first tubing disposed between the first rubber plug unit and the second rubber plug unit, and a second tubing disposed between the second rubber plug unit and the first water control completion unit.

[0036] The volume of the first oil pipe is equal to the volume of the first plugging agent;

[0037] The volume of the second oil pipe is equal to the volume of the second plugging agent.

[0038] As a second aspect of the present invention, the present invention provides an apparatus for establishing a chemical packer in the outer annulus of a screen tube, comprising an oil pipe and a tubing string for establishing a chemical packer in the outer annulus of a screen tube as described above;

[0039] The oil pipe is connected to the tubing string that forms a chemical packer in the outer annulus of the screen pipe.

[0040] As a third aspect of the present invention, the present invention provides a method for establishing a chemical packer in the outer annulus of a sieve tube, which is implemented using the aforementioned tubular column for establishing the chemical packer in the outer annulus of the sieve tube.

[0041] As a fourth aspect of the present invention, the present invention provides an application of a string for establishing a chemical packer in the outer annulus of the screen tube as described above in screen tube well completion.

[0042] Based on the above technical solution, the beneficial effects of the present invention compared with the prior art are as follows: The tubing string for establishing a chemical packer in the annulus of the screen pipe provided in the embodiments of the present invention, through at least one rubber plug unit set at the front end of the tubing string and at least one water control completion unit set at the rear end of the tubing string, allows the two packers to be seated on the screen pipe in the use state. Under the action of the first hydraulic pressure, the first control rubber plug and the second control rubber plug can descend to the position of the constant pressure switch valve. Under the action of the second hydraulic pressure, the first control rubber plug descends and squeezes the plugging agent, causing the plugging agent to flow out through the constant pressure switch valve. The outflowing plugging agent can react with the formation water in the annulus of the screen pipe to seal the annulus, thereby establishing a chemical packer in the annulus of the screen pipe, realizing axial flow control of the annulus of the screen pipe, facilitating the implementation of subsequent water plugging and other operations under the conditions of screen pipe completion; moreover, it is conducive to production recovery, extends the service life of oil and gas wells, and can significantly reduce the development and production costs of oilfields and improve economic benefits. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the structure of the tubular column for establishing a chemical packer in the outer annulus of the sieve tube provided in an embodiment of the present invention;

[0044] Figure 2 yes Figure 1 The diagram shows the structure of the first and second control rubber plugs.

[0045] Figure 3 yes Figure 1 The diagram shown is a structural schematic of a constant pressure switching valve.

[0046] In the diagram: 1. First rubber plug unit; 2. Second rubber plug unit; 3. First water control completion unit; 4. Second water control completion unit; 5. Pressure-regulating foot valve; 6. Guide shoe; 7. First tubing; 8. Second tubing; 9. Slotted screen pipe; 10. Tubing; 11. Casing;

[0047] 10. First control stopper; 20. Second control stopper; 30. Blocking agent; 40. Isolation fluid; 50. Packer; 60. Constant pressure switch valve; 70. Cylinder;

[0048] 101. Connector; 102. Short section; 103. Rubber stopper cap; 104. Rubber stopper shear pin; 105. First seal; 106. Second seal; 107. Third seal; 108. Rubber stopper assembly; 109. Rubber stopper; 110. Core tube; 111. Rubber stopper sleeve; 112. Rubber stopper base; 113. Fourth seal; 114. Plug shear pin; 115. Plug;

[0049] 201. Upper connector; 202. Lower connector; 203. Connecting sleeve; 204. Piston assembly; 205. Liquid outlet; 206. Outer pin; 207. Outer piston; 208. Spring; 209. Connecting ring; 210. Inner piston; 211. Inner pin; 212. Fifth seal. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0051] Example 1

[0052] This invention provides a tubular column for establishing a chemical packer in the outer annulus of a sieve tube, such as... Figure 1 As shown, it includes at least one rubber plug unit disposed at the front end of the tubing string and at least one water control completion unit disposed at the rear end of the tubing string.

[0053] The rubber stopper unit includes a cylinder 70, a first control rubber stopper 10, a second control rubber stopper 20, and a plugging agent 30. The first control rubber stopper 10 and the second control rubber stopper 20 are respectively connected to both ends of the cylinder 70, and the plugging agent 30 is disposed between the first control rubber stopper 10 and the second control rubber stopper 20.

[0054] The water control completion unit includes a constant pressure switching valve 60 and two packers 50, wherein the constant pressure switching valve 60 is connected between the two packers 50;

[0055] In use, the two packers 50 are seated on the screen tube. Under the action of the first hydraulic pressure, the first control plug 10 and the second control plug 20 can descend to the position of the constant pressure switch valve 60. Under the action of the second hydraulic pressure, the first control plug 10 descends and squeezes the plugging agent 30, causing the plugging agent 30 to flow out through the constant pressure switch valve 60. The second hydraulic pressure is greater than the first hydraulic pressure.

[0056] The tubing string for establishing a chemical packer in the outer annulus of a screen pipe (hereinafter referred to as the well string) provided in this embodiment of the invention can be applied to establishing a chemical packer in the outer annulus of slotted screen pipes, borehole screen pipes, or other types of screen pipes. This embodiment of the invention is based on establishing a chemical packer in the outer annulus of a slotted screen pipe. By connecting two packers 50 to a constant pressure switching valve 60, the wellbore section of a horizontal well with a slotted screen pipe completion can be segmented. A rubber plug unit is connected to the upper end of the packer 50, and the rubber plug unit is filled with plugging agent 30, which can be released into the section of the well to be modified. After the insertion string enters the slotted screen section of the wellbore, the packer 50 is set. Thus, the constant pressure switching valve 60 between adjacent packers 50 corresponds to each set section of the slotted screen. Simultaneously with the packer 50 setting, fluid pushes at least one rubber plug unit to the corresponding constant pressure switching valve 60. The constant pressure switching valve 60 then applies plugging agent 30 to the slotted screen section. The plugging agent 30 is forced into the outer annulus of the slotted screen and reacts with formation water to solidify, achieving water control stimulation. This is beneficial for production recovery, extends the service life of oil and gas wells, and significantly reduces production costs and improves economic efficiency in oilfield development.

[0057] In this embodiment of the invention, the constant pressure switch valve 60 is set to the closed state when it enters the well. By opening the constant pressure switch valve 60, the slotted screen section can be connected to the wellbore; by closing the constant pressure switch valve 60, the slotted screen section can be isolated from the wellbore. After the packer 50 is lowered to a preset depth, the packer element on the packer 50 expands through hydraulic drive to seal the annular space between the tubing 10 and the slotted screen 9.

[0058] The packer 50 described in this embodiment of the invention is a simultaneous hydraulic setting device, suitable for vertical wells, highly deviated wells, and horizontal wells. Regarding the selection of the setting position for the packer 50 in slotted screen completions, this embodiment of the invention places the packer 50 at the blind pipe position where the two slotted screens 9 connect.

[0059] As a specific embodiment, the packer 50 is a hydraulic expansion packer. After the hydraulic expansion packer reaches a preset depth, pressure is applied from the oil pipe. The high-pressure liquid acts on the inner cavity of the rubber sleeve through the pressure transmission orifice inside the packer 50. Under the effect of the throttling pressure difference, the rubber sleeve expands to seal the annular space between the oil pipe 10 and the slotted screen pipe 9. When the oil pressure is released and the oil jacket pressure is balanced, the rubber sleeve contracts back to its original shape by its own elasticity, thus releasing the seal. In this embodiment of the invention, the specific structure of the packer 50 can be referred to the detailed description in the prior art. Those skilled in the art can choose according to actual needs. In this embodiment of the invention, no specific limitation is made.

[0060] In this embodiment of the invention, the pressure regulating switch valve 60 and the packer 50 are closely connected. The distance between the pressure regulating switch valve 60 and the packer 50 should be shortened as much as possible to minimize the accumulation of residual liquid between the pressure regulating switch valve 60 and the packer 50 when injecting the plugging agent 30 in stages, thereby reducing the risk of stuck well tubing during well tripping operations.

[0061] In one embodiment, such as Figure 1 As shown, the rubber stopper unit further includes a separating liquid 40 disposed between the plugging agent 30 and the first control rubber stopper 10 and between the plugging agent 30 and the second control rubber stopper 20, respectively. The separating liquid 40 is used to separate the plugging agent 30 from the first control rubber stopper 10 and the second control rubber stopper 20.

[0062] In one embodiment, such as Figure 2 As shown, both the first control rubber plug 10 and the second control rubber plug 20 include a connector 101, a short section 102, a rubber plug assembly 108, and a plug 115;

[0063] The short section 102 is connected to the connector 101;

[0064] The rubber stopper assembly 108 is disposed inside the short section 102 and is connected to the short section 102 by the rubber stopper cutter 104;

[0065] The plug 115 is disposed at the tail end of the rubber stopper assembly 108 and is connected to the rubber stopper assembly 108 via a plug shear pin 114.

[0066] In this embodiment of the invention, when the pressure reaches the shearing opening pressure of the rubber stopper 104, the rubber stopper assembly 108 can move relative to the short section 102; when the pressure reaches the shearing opening pressure of the plug 114, the plug 115 can move relative to the rubber stopper assembly 108; the shearing opening pressure of the plug 114 is greater than the shearing opening pressure of the rubber stopper 104.

[0067] In one embodiment, such as Figure 2As shown, the rubber stopper assembly 108 includes a rubber stopper cap 103, a rubber stopper 109, a rubber stopper base 112, a core tube 110, and a rubber stopper sleeve 111;

[0068] The rubber stopper cap 103 and the rubber stopper base 112 are respectively connected to the two ends of the core tube 110, and the rubber stopper cap 103 is connected to the short section 102 through the rubber stopper shear pin 104;

[0069] The rubber stopper 109 is disposed outside the core tube 110 and is connected to the rubber stopper cap 103 and the rubber stopper base 112 respectively. The rubber stopper 109 abuts against the inner wall of the short section 102.

[0070] The rubber stopper sleeve 111 is connected to the rubber stopper cap 103 and the rubber stopper 109 respectively;

[0071] The plug 115 is disposed inside the rubber stopper base 112 and is connected to the rubber stopper base 112 by the plug shear pin 114.

[0072] In one embodiment, such as Figure 2 As shown, a first sealing element 105 is provided between the short section 102 and the connector 101; a second sealing element 106 is provided between the rubber stopper cap 103 and the short section 102; a third sealing element 107 is provided between the core tube 110 and the rubber stopper cap 103, and between the core tube 110 and the rubber stopper base 112; and a fourth sealing element 113 is provided between the plug 115 and the rubber stopper base 112. The specific structures of the first sealing element 105, the second sealing element 106, the third sealing element 107, and the fourth sealing element 113 can be referred to the description in the prior art. Here, no specific limitation is made; for example, they can be O-rings.

[0073] In one embodiment, such as Figure 3 As shown, the constant pressure switching valve 60 includes an upper connector 201, a lower connector 202, a connecting sleeve 203, and a piston assembly 204;

[0074] The upper connector 201 and the lower connector 202 are respectively connected to the two ends of the connecting sleeve 203;

[0075] The connecting sleeve 203 is provided with a liquid outlet hole 205, and the piston assembly 204 is provided correspondingly to the liquid outlet hole 205 and is connected to the connecting sleeve 203 by an outer pin 206.

[0076] In this embodiment of the invention, when the constant pressure switch valve 60 is not open, the liquid outlet 205 is blocked by the piston assembly 204; when the pressure reaches the shearing start pressure of the outer pin 206, the piston assembly 204 moves relative to the connecting sleeve 203, the liquid outlet 205 is exposed, the constant pressure switch valve 60 is opened, and the plugging agent flows out through the liquid outlet 205.

[0077] In one embodiment, such as Figure 3 As shown, the piston assembly 204 includes an outer piston 207, a spring 208, and a connecting ring 209;

[0078] The outer piston 207 is connected to the connecting sleeve 203 via the outer pin 206, and the size of the lower connector 202 matches the size of the rubber plug 109 of the second control rubber plug 20.

[0079] The connecting ring 209 is connected to the lower connector 202;

[0080] One end of the spring 208 is fixedly connected to the connecting ring 209, and the other end abuts against the outer piston 207.

[0081] In this embodiment of the invention, when the constant pressure switch valve 60 is not open, the outlet hole 205 is blocked by the outer piston 207; when the pressure reaches the shearing start pressure of the outer pin 206, the outer piston 207 moves relative to the connecting sleeve 203, the outlet hole 205 is exposed, the constant pressure switch valve 60 opens, and the plugging agent 30 flows out through the outlet hole 205. After depressurization, the outer piston 207 automatically resets under the action of the spring 208, and the constant pressure switch valve 60 closes. The size of the lower connector 202 matches the size of the rubber plug 109 of the second control rubber plug 20, so that when the rubber plug 109 of the second control rubber plug 20 descends to the lower connector 202, it can sit on the step of the lower connector 202.

[0082] In one embodiment, such as Figure 3 As shown, the constant pressure switching valve 60 also includes an inner piston 210;

[0083] The inner piston 210 is disposed inside the connecting sleeve 203 and is connected to the connecting sleeve 203 by an inner pin 211;

[0084] The dimensions of the inner piston 210 are matched with the dimensions of the rubber stopper 109 of the first control rubber stopper 10.

[0085] In this embodiment of the invention, when the pressure reaches the shearing initiation pressure of the inner pin 211, the inner piston 210 moves relative to the connecting sleeve 203, squeezing out the sealing agent 30 through the outlet hole 205. The size of the inner piston 210 matches the size of the rubber stopper 109 of the first control rubber stopper 10, so that when the rubber stopper 109 of the first control rubber stopper 10 descends to the inner piston 210, it can sit on the step of the inner piston 210, and the downward movement of the inner piston 210 closes the passage between the constant pressure switch valve 60 and the outlet hole 205. The shearing initiation pressure of the inner pin 211 is greater than the shearing initiation pressure of the outer pin 206.

[0086] In one embodiment, such as Figure 3As shown, a fifth sealing element 212 is provided between the upper connector 201 and the connecting sleeve 203, between the inner piston 210 and the connecting sleeve 203, between the lower connector 202 and the connecting sleeve 203, and between the connecting sleeve 203 and the outer piston 207. The specific structure of the fifth sealing element 212 can be referred to the description in the prior art, for example, it can be an O-ring.

[0087] In one embodiment, such as Figure 1 As shown, the string for establishing a chemical packer in the outer annulus of the screen tube also includes a constant pressure bottom valve 5. The constant pressure bottom valve 5 is located at the tail end of the water control completion unit and is connected to the water control completion unit. After the plugging agent 30 is injected, the valve core of the constant pressure bottom valve 5 can be knocked off by pressurizing to perform circulation flushing, washing the residual plugging agent in the casing 11 to the surface.

[0088] In one embodiment, such as Figure 1 As shown, the string for establishing a chemical packer in the outer annulus of the screen tube also includes a guide shoe 6, which is connected to the pressure-regulating bottom valve 5. When the drill pipe carries the well string down into the well, the guide shoe 6 can effectively reduce the occurrence of the lower end of the segmented well string getting stuck. The specific structure of the pressure-regulating bottom valve 5 can be found in the detailed description in the prior art. Those skilled in the art can select according to actual needs; however, in this embodiment of the invention, no specific limitation is made.

[0089] In one embodiment, such as Figure 1 As shown, the at least one rubber stopper unit includes a first rubber stopper unit 1 and a second rubber stopper unit 2, and the at least one water-controlled well completion unit includes a first water-controlled well completion unit 3 and a second water-controlled well completion unit 4.

[0090] The distance between the first rubber plug unit 1 and the second rubber plug unit 2 is the same as the distance between the first water-controlled well completion unit 3 and the second water-controlled well completion unit 4;

[0091] The first rubber stopper unit 1 includes a first plugging agent, and the second rubber stopper unit 2 includes a second plugging agent.

[0092] The string provided in this embodiment of the invention, which establishes a chemical packer in the outer annulus of the screen pipe, allows the slotted screen pipe section to be segmented by lowering the string into a predetermined position, achieving segmented water control. After the packer 50 is set, the constant pressure injection valve 60 is opened sequentially, and then the modification fluid (i.e., plugging agent 30) is injected into the slotted screen pipe section corresponding to the constant pressure injection valve 60. After the modification fluid is injected, the constant pressure switch valve 60 channel can be closed sequentially using the plugs 109 of the first control rubber plug 10 and the second control rubber plug 20 to prevent the plugging agent 30 from flowing back. Then, the plugs 115 of the first control rubber plug 10 and the second control rubber plug 20, and the valve core of the constant pressure foot valve 5 are all knocked off to make the upper and lower parts of the string connected. Circulation flushing circulates the residual plugging agent in the annular space between the tubing 10 and the casing 11 to the surface, and the string is then retrieved. The embodiments of the present invention can quickly and accurately establish a chemical packer in the annulus outside the slotted screen tube, and can establish two-stage chemical packers in one run of the tube, which greatly reduces the operating cost.

[0093] To further describe the tubular structure for establishing a chemical packer in the outer annulus of the sieve tube as described above, this embodiment of the invention provides further explanation and description of the process for establishing a chemical packer in the outer annulus of the sieve tube.

[0094] The pressure control valve 60 (hereinafter referred to as A pressure control valve) of the first water control completion unit 3 and the pressure control valve 60 (hereinafter referred to as B pressure control valve) of the second water control completion unit 4 are used to control the switch inside the well tubing. They are used in conjunction with the first rubber plug unit 1 and the second rubber plug unit 2. The switching method is hydraulic. When A pressure control valve and B pressure control valve are inserted into the well, they are set to the closed state.

[0095] The process flow for establishing a chemical packer in the outer annulus of the sieve tube is as follows:

[0096] 1. Hydraulic pressure within the tubing 10 pushes the first rubber plug unit 1 and the second rubber plug unit 2 downwards. When the second control rubber plug 20 of the second rubber plug unit 2 enters the B constant pressure switch valve and sits still on the step inside the lower connector 202, hydraulic pressure continues to be applied within the tubing 10. When the pressure reaches the shearing opening pressure of the outer pin 206, the outer piston 207 of the B constant pressure switch valve moves downwards, and the B constant pressure switch valve opens. The second plugging agent in the second rubber plug unit 2 enters the annulus of the segmented modified slotted screen pipe and reacts with the formation water to seal the annulus of that segment.

[0097] 2. Continue to increase the hydraulic pressure so that the first control plug 10 of the second plug unit 2 enters the B constant pressure switch valve and sits still on the inner step of the inner piston 210. Continue to increase the hydraulic pressure until the shearing opening pressure of the inner pin 211 is reached, so that the inner piston 210 moves downward to squeeze the second plugging agent out. After the second plugging agent is squeezed out, close the channel between the B constant pressure switch valve and the outlet hole 205; the outer piston 207 automatically resets under the action of the spring 208, and the B constant pressure switch valve closes.

[0098] 3. Hydraulic pressure in the oil pipe 10 pushes the first rubber plug unit 1 downward. When the second control rubber plug 20 of the first rubber plug unit 1 enters the A constant pressure switch valve and sits still on the step in the lower connector 202, hydraulic pressure continues to be applied in the oil pipe 10. When the pressure reaches the shearing opening pressure of the outer pin 206, the outer piston 207 of the A constant pressure switch valve moves downward and the A constant pressure switch valve opens. The first plugging agent in the first rubber plug unit 1 enters the annulus of the segmented modified slotted screen pipe and reacts with the formation water to seal the annulus of that segment.

[0099] 4. Continue to increase the hydraulic pressure. The first control plug 10 of the first plug unit 1 enters the A constant pressure switch valve and remains stationary on the inner step of the inner piston 210. Continue to apply hydraulic pressure to the oil pipe 10. When the shearing opening pressure of the inner pin 211 is reached, the inner piston 210 moves downward, squeezing out the first plugging agent and closing the channel between the A constant pressure switch valve and the outlet hole 205. The outer piston 207 automatically resets under the action of the spring 208, and the A constant pressure switch valve closes. The closure of the A constant pressure switch valve prevents the first plugging agent from flowing back, ensuring the safety of the entire operation.

[0100] In one embodiment, after the segmented modification is completed, the internal channels of the first rubber plug unit 1, the second rubber plug unit 2, and the pressure-regulating bottom valve 3 are opened to establish a circulation channel, enabling the inside of the wellbore string to connect with the outside. Specifically, after the segmented modification is completed, during the wellbore string retrieval operation, the plugs 115 of the first rubber plug unit 1 and the second rubber plug unit 2, as well as the valve core of the pressure-regulating bottom valve 5, are removed to establish a circulation channel. The tubing 10 and the casing annulus (the annular space between the tubing and the casing) are connected, establishing a circulation channel from the casing annulus to the tubing 10. This circulation channel can wash the residual plugging agent in the casing to the surface, reducing the risk of jamming during the retrieval of the segmented modification string and facilitating the string retrieval. After the wellbore string is retrieved, the original wellbore diameter is restored, reserving a technical window for later production control, water control, further segmented modification, and other operations.

[0101] In one embodiment, such as Figure 1 As shown, the string for establishing a chemical packer in the outer annulus of the screen tube also includes a first tubing 7 disposed between the first rubber plug unit 1 and the second rubber plug unit 2, and a second tubing 8 disposed between the second rubber plug unit 2 and the first water control completion unit 3.

[0102] The volume of the first oil pipe 7 is equal to the volume of the first plugging agent;

[0103] The volume of the second oil pipe 8 is equal to the volume of the second plugging agent.

[0104] In one embodiment, the dimensions of the first control plug 10 and the second control plug 20 of the first plug unit 1 are larger than the dimensions of the first control plug 10 and the second control plug 20 of the second plug unit 2. During the segmented modification process, the first control plug 10 and the second control plug 20 of the second plug unit 2 will pass through pressure switch valve A to pressure switch valve B. The dimensions of the first control plug 10 and the second control plug 20 of the second plug unit 2 will be smaller than the dimensions of the first control plug 10 and the second control plug 20 of the first plug unit 1, so that the first control plug 10 and the second control plug 20 of the second plug unit 2 can pass smoothly through pressure switch valve A.

[0105] Example 2

[0106] Based on the same inventive concept, such as Figure 1 As shown, an embodiment of the present invention provides an apparatus for establishing a chemical packer in the outer annulus of a screen tube, including an oil pipe 10 and a tubing string for establishing a chemical packer in the outer annulus of a screen tube as described above;

[0107] The oil pipe 10 is connected to the tubing string that forms a chemical packer in the outer annulus of the screen pipe.

[0108] In one embodiment, the tubing 10 and the string for establishing a chemical packer in the outer annulus of the screen tube can be connected by a threaded connection or a screw thread connection. Of course, in this embodiment of the invention, the method of fixing the tubing 10 and the string for establishing a chemical packer in the outer annulus of the screen tube can be described in detail in the prior art, and is not specifically limited here.

[0109] The specific implementation of the device for establishing a chemical packer in the outer annulus of the sieve tube provided in the embodiments of the present invention can be referred to the detailed description of the tubular column for establishing a chemical packer in the outer annulus of the sieve tube in the above embodiments. Where the description is repeated, it will not be repeated.

[0110] This invention also provides a method for establishing a chemical packer in the outer annulus of a sieve tube, which is achieved using the aforementioned tubular string for establishing a chemical packer in the outer annulus of a sieve tube. The method includes:

[0111] Lower the string of the chemical packer into the outer annulus of the sieve tube to the designated position;

[0112] The oil pipe 10 was pressurized and a chemical packer was established in the annulus outside the screen pipe for segmental modification;

[0113] After the segmented modification is completed, the tubing for establishing a chemical packer is removed from the outer annulus of the screen tube.

[0114] The specific implementation of the method for establishing a chemical packer in the outer annulus of the sieve tube provided in the embodiments of the present invention can be referred to the detailed description of the tubular column for establishing a chemical packer in the outer annulus of the sieve tube in the above embodiments. Where the description is repeated, it will not be repeated.

[0115] This invention also provides an application of a string for establishing a chemical packer in the outer annulus of the screen tube as described above in screen tube well completion.

[0116] In the detailed description above, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features in a single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, with each claim representing a separate preferred embodiment of the invention.

[0117] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term "comprising" as used in the specification or claims is interpreted in a manner similar to the term "including," as interpreted when used as a conjunction in the claims. Additionally, the use of any term "or" in the specification of the claims is intended to mean "non-exclusive or."

Claims

1. A tubular column for establishing a chemical packer in the outer annulus of a sieve tube, characterized in that, It includes at least one rubber plug unit disposed at the front end of the tubing string and at least one water control completion unit disposed at the rear end of the tubing string; The rubber stopper unit includes a cylindrical body, a first control rubber stopper, a second control rubber stopper, and a plugging agent; the first control rubber stopper and the second control rubber stopper are respectively connected to both ends of the cylindrical body, and the plugging agent is disposed between the first control rubber stopper and the second control rubber stopper; both the first control rubber stopper and the second control rubber stopper include a connector, a short section, a rubber stopper assembly, and a plug; the short section is connected to the connector; the rubber stopper assembly is disposed inside the short section and is connected to the short section by a rubber stopper shear pin; the plug is disposed at the tail end of the rubber stopper assembly and is connected to the rubber stopper assembly by a plug shear pin; The water-controlled completion unit includes a constant pressure switching valve and two packers, with the constant pressure switching valve connected between the two packers. The constant pressure switching valve includes an upper connector, a lower connector, a connecting sleeve, and a piston assembly. The upper connector and the lower connector are respectively connected to both ends of the connecting sleeve. The connecting sleeve has a liquid outlet, and the piston assembly is correspondingly positioned to the liquid outlet and connected to the connecting sleeve via an external pin. The piston assembly includes an outer piston, a spring, and a connecting ring. The outer piston is connected to the connecting sleeve via the external pin. The size of the lower connector matches the size of the second control rubber plug. The connecting ring is connected to the lower connector. One end of the spring is fixedly connected to the connecting ring, and the other end abuts against the outer piston. In use, the two packers are seated on the screen tube. Under the action of the first hydraulic pressure, the first control plug and the second control plug can descend to the position of the constant pressure switch valve. Under the action of the second hydraulic pressure, the first control plug descends and squeezes the plugging agent, causing the plugging agent to flow out through the constant pressure switch valve. The second hydraulic pressure is greater than the first hydraulic pressure.

2. The tubular string for establishing a chemical packer in the outer annulus of the sieve tube according to claim 1, characterized in that, The rubber stopper unit also includes a separating fluid disposed between the plugging agent and the first control rubber stopper and between the plugging agent and the second control rubber stopper.

3. The tubular string for establishing a chemical packer in the outer annulus of the sieve tube according to claim 1, characterized in that, The rubber stopper assembly includes a rubber stopper cap, a rubber stopper, a rubber stopper base, a core tube, and a rubber stopper sleeve; The rubber stopper cap and the rubber stopper base are respectively connected to both ends of the core tube, and the rubber stopper cap is connected to the short section through the rubber stopper shear pin; The rubber stopper is disposed outside the core tube and is connected to the rubber stopper cap and the rubber stopper base respectively, and the rubber stopper abuts against the inner wall of the short section; The rubber stopper sleeve is connected to the rubber stopper cap and the rubber stopper respectively; The plug is disposed inside the rubber stopper base and is connected to the rubber stopper base by the plug shear pin.

4. The tubular string for establishing a chemical packer in the outer annulus of the sieve tube according to claim 3, characterized in that, A first sealing element is provided between the short section and the connector, a second sealing element is provided between the rubber stopper cap and the short section, a third sealing element is provided between the core tube and the rubber stopper cap and between the core tube and the rubber stopper base, and a fourth sealing element is provided between the plug and the rubber stopper base.

5. The tubular string for establishing a chemical packer in the outer annulus of the sieve tube according to claim 1, characterized in that, The constant pressure switching valve also includes an internal piston; The inner piston is disposed inside the connecting sleeve and is connected to the connecting sleeve by an inner pin; The size of the inner piston matches the size of the rubber stopper of the first control stopper.

6. The tubular string for establishing a chemical packer in the outer annulus of the sieve tube according to claim 5, characterized in that, A fifth sealing element is provided between the upper connector and the connecting sleeve, between the inner piston and the connecting sleeve, between the lower connector and the connecting sleeve, and between the connecting sleeve and the outer piston.

7. The tubular string for establishing a chemical packer in the outer annulus of the sieve tube according to claim 1, characterized in that, It also includes a constant pressure bottom valve, which is located at the tail end of the water control completion unit and connected to the water control completion unit.

8. The tubular string for establishing a chemical packer in the outer annulus of the sieve tube according to claim 7, characterized in that, It also includes a guide shoe, which is connected to the constant pressure bottom valve.

9. The tubular string for establishing a chemical packer in the outer annulus of the sieve tube according to claim 1, characterized in that, The at least one rubber plug unit includes a first rubber plug unit and a second rubber plug unit, and the at least one water-controlled well completion unit includes a first water-controlled well completion unit and a second water-controlled well completion unit; The distance between the first rubber plug unit and the second rubber plug unit is the same as the distance between the first water-controlled completion unit and the second water-controlled completion unit; The first rubber stopper unit includes a first plugging agent, and the second rubber stopper unit includes a second plugging agent.

10. The tubular string for establishing a chemical packer in the outer annulus of the sieve tube according to claim 9, characterized in that, It also includes a first tubing disposed between the first rubber plug unit and the second rubber plug unit, and a second tubing disposed between the second rubber plug unit and the first water control completion unit; The volume of the first oil pipe is equal to the volume of the first plugging agent; The volume of the second oil pipe is equal to the volume of the second plugging agent.

11. An apparatus for establishing a chemical packer in the outer annulus of a sieve tube, characterized in that, Includes tubing and a tubing string for establishing a chemical packer in the annulus outside the screen tube as described in any one of claims 1-10; The oil pipe is connected to the tubing string that forms a chemical packer in the outer annulus of the screen pipe.

12. A method for establishing a chemical packer in the outer annulus of a sieve tube, characterized in that, This is achieved using a tubular column that establishes a chemical packer in the outer annulus of the sieve tube as described in any one of claims 1-10.

13. The application of the string for establishing a chemical packer in the outer annulus of the screen pipe according to any one of claims 1-10 in screen pipe completion.

Images